Power driven ridge reamer



Sept. 1, 1964 c. c. RENFROE 3,146,562

' POWER DRIVEN RIDGE REAMER Filed Nov. 8, 1961 2 Sheets-Sheet 1 INVENTOR. CHAiQRENFHOE.

P 1, 1964 c. c. RENFROE 3,146,562

POWER DRIVEN RIDGE REAMER Filed Nov. 8, 1961 2 Sheets-Sheet 2 INVENTOR. CHAS. C. RENFROE.

A TTO RNEYS.

United States Patent 3,l4ti,562 PQWER DPJVEN RIDGE REAMER Charles C. Renfroe, 1321 Edgerly Ave, Albany, Ga. Filed Nov. 8, 1961, er. No. 151,022 10 Claims. (Cl. 51-441) This invention relates to a machine for removing the ridge which forms after much use on the cylinder walls of a pump or internal combustion engine cylinder. This ridge is caused by piston rings wearing the cylinder walls or causing uneven wear on the cylinder walls so that said cylinder Walls are not cylindrical.

An object of the invention, therefore, is to provide a power-driven tool for the removal of the ridge from the top of the cylinder caused by piston ring wear, and to true up the cylinder walls.

Other objects will hereinafter appear throughout the specification.

In the drawings:

FIGURE 1 is a perspective view of the machine with parts broken away;

FIGURE 2 is an enlarged perspective view with parts broken away of the driving means of the machine showing the worm and worm gear separated from each other for purposes of illustration;

FIGURE 3 is a perspective view, partly broken away, of the lower end of the machine;

FIGURE 4 is an enlarged perspective view of one of the tools and its support with a portion of the cylinder shown in section; and

FIGURE 5 is an exploded view of the tool and its supporting means;

FIGURE 6 is a diagrammatic view, partly in section, with parts omitted of a second form of holding means; and

FIGURE 7 is a top plan view of the lower end of the second form of the invention.

Any automobile mechanic knows that the piston rings after considerable use cause a ridge to be formed on the cylinder walls due to wearing of the rings against the said walls. The same is also true of pumps and other reciprocating types of devices which include cylinders and pistons. This ridge usually extends from the top of the piston ring travel area in the cylinder upward to the top of the cylinder block. This ridge must be cut away flush with the cylinder wall at the time of the engine overhaul or piston ring replacement, to prevent damage to the pistons when being removed from the engine cylinders, and to prevent damage to the new piston rings and possibly the pistons as well after replacement and in order to prevent severe knocking in the engine caused by the top of the uppermost piston ring striking the bottom of the ridge, assuming the same has not been removed or has partially or improperly been removed.

Present types of ridge removing devices have proved inadequate. Hand-operated tools in use today are both time and energy consuming. Moreover, it is necessary to use them in the confined working spaces of the engine compartment. Because of the fact that the present handoperated ridge reamer must be turned by means of a socket wrench and handle attached to the tool, power is applied off to the side of the tool, and when used in confined areas where it is impossible to use both hands to steady the tool, tilting often occurs at the tool end of the device and either damage to the cylinder wall or an incomplete cutting job results with the said tool movements.

The tool of the present invention will remove all of the ridge and nothing but the ridge under all conditions no matter how confined the area or how severe the out-ofroundness of the cylinder may be, with a minimum of time and effort.

The invention envisages the use of a pair of opposed cutters which operate under spring pressure to prevent any side pressure on the body of the tool, and consequently no tilting of the tool. Additionally, because of its compactness the inaccessible places can be reached with even tool pressure and even cutting which results in a finished process under all conditions of use. In each case, the entire ridge is removed.

The power tool of this invention may be operated by either a A or /8" electric drill, which drills are always available to any mechanic in a motor repair shop. Because of the fact that the device does not have a selfcontained power unit, such as an electric motor directly attached to its shaft, it can be made sufficiently compact to be used in confined areas. The cost of accomplishing the purposes of the invention may be had at a price which will not be prohibitive to the customer or the mechanic or shop owner who does the work.

Referring now to the drawings, see FIGURES 1 and 4, letter A indicates a portion of the engine or pump including the cylinder walls. Numeral 1 shows the main body or housing of the device which is supported by an adjustable framework 7 that may be mounted in a suitable manner on the engine or pump block. Pressed or threaded in the main body housing 1 is a support tube 2 which houses bolt 26a. This tube acts as a support or bearing surface about which the cutting tools revolve. Numeral 3 indicates a lock nut for holding the parts in proper position. Lock nut 3 and housing 1 are preferably independently threaded on tube 2.

As shown in FIGURES 1 and 2, numeral 4 indicates a worm drive shaft which is supported by a bronze bushing that is rigid with the housing 1. This drive shaft at its left end as seen in FIGURES 1 and 2 is mounted on an adjustable bronze bushing and thrust washer with a lock nut on the free end indicated by reference numeral 5. i The shaft 4 is driven by a flexible drive shaft 6 whose opposite ends, not shown, is connected to a suitable source of power, such as an electric motor.

The base of the machine is provided with an adjustable foot assembly, two being shown in the drawings. This assembly comprises three or more cylinder wall engaging feet 23 held in their contracted position by a contractable spring or bar 31. These feet 28 are forced outward by the cone 29 which comprises a plurality of cone sections that may be moved upwardly or downwardly by operation of the screw which is directly connected to the handle 26 and which may be rotated thereby in either direction. When the handle 26 is operated it rotates the screw which expands the feet to engage the cylinder wall below where the reaming operation will take place and fixes the machine centrally of the cylinder, or in line with the longitudinal axis thereof. This is the fixed position that the machine remains in during the removal of the ridge B of the cylinder walls shown in FIGURES 1 and 4. The adjustable foot assembly upon expansion fixes the stationary parts rigidly in the cylinder and anchors the main body 1 .of the device in fixed position.

Each backing bar is urged resiliently outwardly by a spring-urged lug 15 located within housing 17. Each lug 15 is urged by a spring 18 so that each backing bar is biased towards the cylinder wall.

The nut 3 is used for the purpose of regulating the operating clearance between members 1 and 11 and for bringing O-ring member 10 between these members. It will be understood that the upper portion or section including the foot 7 and the casing supported thereby will be stationary, and that the feet will anchor the lower por tion of the device so that it will also be stationary.

Between the upper and lower section is the rotating section or tool-supporting body 11. The upper portion of this body is separated from the main body housing by the Q O-ring 11 which fits in facing grooves, not shown, in the two bodies. The rotating tool body is rotated by the worm gear drive 12.

The worm 36 which is driven by shaft 4 meshes with the worm gear 12. These parts have been shown in partially separated positions whereby casing 1 is separated from casing 11, solely to show the worm gear 12 which is engaged by the worm 36 when the parts are assembled, as shown in FIGURE 1. The worm gear rotates the tool supporting body 11 to which is attached the cutter assembly cover 16. The numeral 17 indicates a recess for the reception of the cutter pressure spring 18. The cutter housings 16 support two pairs of expandable tool support and tool backing bars 13 and 14. Each backing bar 14 is provided with slots 38 which slide on the screws 19. At one end of each tool bar is an aperture for the reception of the shouldered bolt 23 which mounts the cutter support body 21 for pivotal motion about the unthreaded portion of the shouldered bolt 23. Each cutter is indicated at 22. Each bar assembly consists of a tool support bar and a tool backing bar, and each assembly supports a tool as noted hereinafter. Relative adjustment and locking in adjusted position is accomplished by screws 19.

Each cutter 22 is provided with a boss 40 which fits in an aperture 42 and which may be locked in fixed position by the screw 24, see FIGURE 5. The screw 24, boss 40 and aperture 42 permit adjustment. This is accomplished by loosening screw 24 and partially rotating the cutter on the cutter support body.

Each tool supporting body is provided with a cut-out portion 44 and a head 46. The diameter of the head is approximately about the same diameter as the cutting tool.

It will be appreciated that the tool supporting body is freely pivoted on the shouldered bolt 23.

Reference numeral 30 shows the cone locking pin recess in the lower circumference of the cone 27. The cone locking pin 29 extends downward from an expansion unit body 25 which supports the feet 28. This locking pin engages the sides of the recess to prevent the expansion cone 27 from turning. The lower end of bolt 26a is threaded at 48 which end is screwed through cone 27 as shown in FIGURE 1. With the main body noted at 1 and the lower end of the machine fixed solidly to the lower end of the main body support tube, the locking cone pin 29 engages in the recess 30 locking the cone, i.e. preventing it from turning during the expansion of the cylinder wall engaging feet 28. Clockwise rotation of the knob 26 pulls the cone 27 upward in the expansion unit body 25 fixing the cylinder wall engaging feet 28 outward against the cylinder wall. Counterclockwise rotation will retract the feet inward causing the tapered ends of the feet to lower the cone 27.

Operation When the size of the cylinder bore is determined, the tool support bar 13 is slid on the backing bar 14. The bars of each assembly (one bar 13 and one bar 14 with their tool supports) are set by tightening screws 19 thereof.

Stop pin 26 fixed to bar 14 of each assembly prevents undue outward movement of each tool assembly and assists in maintaing spring 18 in proper position whereby it maintains a slight pre-load on each cutter assembly.

The scale 64 is then set by tightening screws 19 so as to correspond to the cylinder bore size. Since the cutter supports or holders 21 are free to move on the shoulders of bolts 23, FIGURES l and 4, they can be moved inward at the bottoms to permit the tool to enter the cylinder. This may be accomplished by pivoting both tool holders 21 so that their heads 46 will clear the shoulder B. As will be noted, each assembly with its cutter holders and cutters, 21 and 22 respectively, is mounted 180 apart on oppositely positioned plates 16 with the heads 46 inclined toward the geometrical center of the cylinder. The machine is then pushed downward, and this downward pressure causes the cutter supports 21 to move outwardly against the top of the cylinder wall and forces the cutter assemblies inward against the springs 13 to enter the cylinder and assume the position shown in FIGURE 1, the cutter supports 21 coming to a vertical position. The inward pushing of the tool support bar 13 and tool support backing bar 14, compresses the cutter assembly pressure springs 13, thus preloading the cutter assemblies for the cutting operation.

In order to reach the proper position for cutting the shoulder B the unit is moved downward into the cylinder until each cutter 22 is the same plane as shoulder B. In this position, the cutter foot assemblies may be adjusted to a position where the feet 28 rest against the cylinder wall, this being accomplished by rotation of the screw 48 by the handle 26. The screws 60 are then adjusted so that the foot assembly 7 rests on the cylinder block of which the cylinder forms a part. No other adjustment is necessary for the remainder of the operation.

Assuming that the knob 26 has been tightened in place and the feet 28 firmly engage the cylinder walls, the motor or other power means, not shown, is started to rotate shaft 6 which drives shaft 4 and the worm 36 mounted thereon. The worm 36 rotates the worm gear 12 which rotates the assembly 16, the latter of which mounts the tool supports and tools 22 driven thereby.

The cutters are fixed in the cutter support bodies so that they do not rotate on their own axes, but the cutters move in a circular path against shoulder B, each cutter being biased to move against the shoulder and away from the rotative center of the rotating tool support body 11.

Since there are two cutter assemblies, from each other, within the cylinder, side thrust against the center of the rotating part 11 is eliminated, and no tilting of the tools 22 is possiblie, or of either cutter assembly.

It will be seen by reference to FIGURE 4 that the bottom or head 46 of the cutter support body contacts the cylinder wall and that cutter 22 is forced against the ridge B of the cylinder, leaving the cut-out portion 44 clear of the cylinder wall. As previously stated, the cutter support body 21 is free to pivot about the shoulder of bolt 23. Thus, as cutting progresses, the upper contact face of the cutter support moves outward toward the cylinder wall as the thickness of the shoulder B is reduced. This upper face on 21 below the cutters is preferrably the same diameter as the cutters. The upper contact face of each cutter is shown at 95.

As previously stated, the diameter of the cutter 22 and the lower head 46 of the support are of the same diameter. Consequently, when the upper contact face of the cutter support 44 touches the cylinder wall no further cutting is possible. This is due to the fact that no matter how badly out-of-round the cylinder may be or how thick or thin the ridge B may be, in different sections around the circumference of the cylinder, as long as there is any ridge or shoulder B left, when the cutter reaches it the upper face of the cutter support 21 automatically moves away from the cylinder wall leaving the cutter free to out even sections of said wall until the upper contact face of the cutter support 21 again touches the cylinder wall. As will be seen by references to FIGURES 1 and 4, the spring pressures applied by the springs 18 to the cutter supports 21 through shoulder bolts 23 is well below cutter 22. Hence, the upper contact face of the cutter support 21 prevents any further cutting action after the contact face of the cutter support touches the cylinder wall.

It is to be understood that the type of cutters are shown merely by way of example and that other types of cutters can be used, such as rotary files, spiral reamers or straight-bladed reamers. Any such cutters if they are mounted in the manner particulraly shown in FIGURE 5 can be repositioned after use to present a sharpened unused area by merely loosening screw 24 and rotating the cutter 22 a short amount. When the cutter has been rotated to present a new sharpened surface to the work the screw 24 may be tightened. Additionally, resharpenable ground type tool bits (cutters) have been used in the unit satisfactorily and, accordingly, the present invention includes any type of cutter which may be mounted on the cutter support-bodies which will present a sharpened edge tothe shoulder B when the tool is rotated by worm drive gear 12 and worm. Tool bit type cutters may be employed but I prefer to use the type of cutters illustrated in the drawings.

When assembling, the rotating tool support body is slipped over the outside of the main body support tube 2 (as shown in FIGURE 2) on which it rotates when in operation, and is secured by turning the tension adjusting nut 8 on the threaded lower end of the screw 48 this being the lower end of the main body support tube. The nut should be adjusted so as to apply sufficient tension against the O-ring or grease seal ring 10. Worm drive gear 4 and worm driven gear 12 are then in proper mesh with each other.

The upper portion 1 of the device is then threaded on to the threaded lower end of the main body support tube 2, and locked tightly against the tension adjusting nut 8. The tension against the O-ring 10 which has been previously adjusted will not be disturbed if the tension adjusting nut 8 is held in its adjusted position by a suitable wrench. The main body housing 1 and the handle 26 and the shaft connecting the same are now an integral fixed part of the stationary unit which includes, of course, the structure shown at 26, 27 and 28 of FIGURE 3. Each cutter assembly or intermediate rotatable section is now attached to the tool support body 11 on opposite ends of the machined surfaces of the body 11 and are held in place by the cutter assembly attaching bolts 70. These centering and securing the unit, operating bolt and knob assembly 26 is slipped through the hollow center of main body support tube 2 and the threaded lower end of the bolt 48 should rest on the upper end of the main body support tube 2 assuming the bolt has come through the bottom of the expansion cone 27. Since the cone 27 is prevented from turning by pin 29, turning knob 26 clockwise pulls the cone 27 upward against the beveled inner ends of feet 28 causing the feet 28 to move outward in gripping engagement of the cylinder wall. When the knob 26 is turned counterclockwise the retaining and retractable spring 31 causes the inner beveled ends of the feet to press against the taper of expansion cone 27 forcing it downward in the expandable unit body 25 and causing feet 28 to move toward the center of the unit and away from the cylinder wall, freeing the machine for removal from the cylinder. It will be understood that when the feet 28 have been caused to grip the cylinder walls the shaft 4 may be rotated by an electric drill shaft to thereby rotate the cutters until the shoulder B has been entirely removed, thus enlarging the cylinder to the size that it had been worn in those portions below the shoulder B.

In the form shown in FIGURES 6 and 7, a modified structure is shown diagrammatically, to take the place of the expandable unit that includes the parts 25, 26, 27, 28 for holding the device and releasing the same from the cylinder walls. It will be understood, however, that certain parts have been omitted for the sake of more clearly illustrating the machine anchoring means. The drive means for orbiting the cutters, the adjustable foot assembly, the means for mounting the same and the cutter adjusting means will form an integral part of the device of FIGURES 6 and 7.

It becomes necessary when using the machine on cylinders of widely differing diameters in a machine shop, to provide an anchoring means that can be adjusted for wide or narrow diameters of cylinders.

An adjustable foot assembly, not shown, corresponding to parts 7 may be provided but any means for anchoring the same in fixed position may be employed. As shown at 72 a disk is shown having a headed locking pin 74 which is urged upwardly by a spring 76. The lower end of the V V 7 pin is adapted to engage in any one of a series of circumferentially spaced apertures 78. The disk 72 is splined at 79 to a torsion shaft 82, i.e. shaft or bolt 82 of spring steel and may be rotated and locked by pin 74 so as to be under tension, as hereinafter explained. At the lower end of shaft 82 is splined a gear 84, which engages teeth 86 and 88 on its opposite sides. Teeth 86 and 88 each form parts of the racks 90 and 92. Mounted on one end of rack 90 is an arm 94, and mounted on one end of rack 92 is an arm 96. Preferably each bar is mounted on top of its rack to permit the other rack to slide under the opposite bar. Arm 94 is provided with hard rubber or plastic bushings 98, and arm 96 is provided with similar bushings 100. Other suitable material than hard rubber or plastic may be substituted for these materials, but the bushings must be of a material which will not injure the cylinder walls of cylinder C. The racks may slide in a housing 1432, which may be similar and similarly mounted to housing 25. The housing 102 has been shown in dotted lines so as to more clearly illustrate the racks and pinion construction of FIGURE 7. The means mounting outer shaft and its drive as well as the tool support bars and tool support backing bars and springs 18, also including the structure shown in FIGURES 4 and 5 will be as illustrated in the first form of the invention. The free ends 1% and 109 of racks and 92 are arc-shaped and assist in gripping the cylinder walls.

Assuming the housing 80 to be held in fixed position, with the racks in retracted position in the cylinder of the engine C, when it is desired to fix the machine in its grinding position Within a cylinder, the disk member is rotated in the direction of the arrows in FIGURE 7, after withdrawal of pin '74 from one of the holes 78. This will rotate pinion 84 until the bushings 98 and engage the cylinder walls. The rotation of the shaft is then continued until the shaft 82 is caused to be in tension, after which the pin 74 is pushed downwardly to engage the nearest hole 78. This action maintains the machine in tightly clamped position against the cylinder walls. Flexible shaft 6 is then rotated by means of a motor, not shown, to rotate or orbit the tools 22 about the geometrical center of the cylinder. It will be understood that the grinding tools diagrammatically oppose each other at and that each of the springs l urges its cutting tool in the opposite direction from the other cutting tool, the two forces equally opposing each other when the tools are in the position of FIGURE 1, and within the limits of adjustrnent by the screws 19.

The cutting tools are adapted solely to cut the shoulder with which they are in engagement, as illustrated in FIG- URE 1, and do not engage the cylinder below the shoulder.

The above description and drawings disclose several embodiments of the invention, and specific language has been employed in describing the several figures. It will, nevertheless, be understood that no limitations of the scope of the invention are thereby contemplated, and that various alterations and modifications may be made such as would occur to one skilled in the art to which the invention relates.

I claim:

1. A machine for removing a ridge in cylinders comprising at least one pair of cutters, means mounting said cutters in opposed position whereby the radial outward movement of one opposes the radial outward movement of the other of the pair of cutters when said cutters are in engagement with the wall of a cylinder, said mounting means including spring means for urging said cutters away from each other, means for causing said cutters and their mounting means to rotate in a circular path about a center, and means for fixing said cutter rotating means on a fixed support, said cutter mounting means including a pivotal support for each cutter for freely rotatably supporting each cutter on a substantially horizontal axis when in cutting position.

2. The structure of claim 1 wherein said means firstnamed includes a head, adjustable foot means located above said cutters and adapted to be mounted on a support, and cylinder Wall engaging feet located below said cutters.

3. The structure of claim 2 wherein wedge means is provided for causing said last-named feet to engage a cylinder wall.

4. The structure of claim 2 wherein sealing means is provided between said head and said cutter mounting means.

5. The structure of claim 1 wherein said means mounting said cutters includes scale means for indicating the adjusted outward limits of said cutters as adjusted by said adjustable means.

6. The structure of claim 1 wherein said last-named means includes a torsion member.

7. The structure of claim 1 wherein said last-named means includes rack and pinion means and torsion means for operating said rack and pinion means.

8. The structure of claim 1 wherein said last-named means includes a torsion shaft, means for applying torsion 8 to said shaft, means for locking said shaft While under torsion, a gear on said shaft and rack means operated by said gear, said rack means having means for clampingly engaging a cylinder wall.

9. The structure of claim 1 wherein said means for causing said cutters to rotate includes a worm, a worm gear driven by said worm, and a flexible shaft for driving said worm.

10. The structure of claim 1 wherein each said cutter has a cutter member at one end and a lower head at the opposite end, said head being adapted to contact a cylinder wall during the operation of each of said cutters.

References Cited in the file of this patent UNITED STATES PATENTS 1,471,808 Russ Oct. 23, 1923 1,722,301 Kavle July 30, 1929 2,040,281 Sunnen May 12, 1936 2,159,918 Warnock May 23, 1939 2,724,283 Kuboske Nov. 22, 1955 

1. A MACHINE FOR REMOVING A RIDGE IN CYLINDERS COMPRISING AT LEAST ONE PAIR OF CUTTERS, MEANS MOUNTING SAID CUTTERS IN OPPOSED POSITION WHEREBY THE RADIAL OUTWARD MOVEMENT OF ONE OPPOSES THE RADIAL OUTWARD MOVEMENT OF THE OTHER OF THE PAIR OF CUTTERS WHEN SAID CUTTERS ARE IN ENGAGEMENT WITH THE WALL OF A CYLINDER, SAID MOUNTING MEANS INCLUDING SPRING MEANS FOR URGING SAID CUTTERS AWAY FROM EACH OTHER, MEANS FOR CAUSING SAID CUTTERS AND THEIR MOUNTING MEANS TO ROTATE IN A CIRCULAR PATH ABOUT A CENTER, AND MEANS FOR FIXING SAID CUTTER ROTATING MEANS ON A FIXED SUPPORT, SAID CUTTER MOUNTING MEANS INCLUDING A PIVOTAL SUPPORT FOR EACH CUTTER FOR FREELY ROTATABLY SUPPORTING EACH CUTTER ON A SUBSTANTIALLY HORIZONTAL AXIS WHEN IN CUTTING POSITION. 